The Nones Have It According to a 2009 study the percentage of Americans claiming no religion, which jumped from 8.2 in 1990 to 14.2 in 2001, has now increased to 15 percent. Given the estimated growth of the American adult population since the last census from 207 million to 228 million, that reflects an additional 4.7 million "Nones." "Many people thought our 2001 finding was an anomaly," [Ariela] Keysar said. We now know it wasn't. The 'Nones' are the only group to have grown in every state of the Union." Source-http://www.americanreligionsurvey-aris.org/